Re: [PATCH v2 0/6] ASoC: extra format on each DAI

[Stephen Gordon <gordoste@xxxxxxxxxxxx>]

On 28/12/2024 10:18 pm, Stephen Gordon wrote:
> On 27/12/2024 11:21 pm, Stephen Gordon wrote:
> > On 23/12/2024 1:01 pm, Kuninori Morimoto wrote:
> > > > [   27.333830] asoc-audio-graph-card2 soc@107c000000:sound: probe with
> > > > driver asoc-audio-graph-card2 failed with error -12
>
> In turn, this is because the linked list of siblings is actually in 
> reverse order due to the way populate_node() (drivers/of/fdt.c) adds 
> them. 

It looks like the node order is fixed up later...
https://github.com/torvalds/linux/blob/fc033cf25e612e840e545f8d5ad2edd6ba613ed5/drivers/of/fdt.c#L330

However drivers/ot/dynamic.c uses similar node insertion code, but 
without any reordering. I guess this is what is used on my machine 
(Raspberry Pi 5) - perhaps your DT is just built differently :)

> I get a playback DAI visible in aplay, however the capture DAI is not 
> visible in arecord. If I swap the order of the codec ports in multi/ 
> ports, then I get a capture DAI visible in arecord, but the playback DAI 
> is missing :)

This was because of the playback-only and capture-only flags in my 
previous DTS. These flags are actually on the dai_link, so specifying 
this flag on a port/endpoint affects the whole link. Since I specified 
both, whichever one is processed last takes effect.

I think we should either:
- Make this a flag at the link level
	e.g. 	links = <&link0 PLAYBACK_ONLY>
or
- Document the behaviour

Anyway, once I removed those flags, the DTS works, as long as the CPU 
port is listed _last_ inside the 'multi' node. This is equivalent to a 
requirement to list the CPU port _first_ on other platforms.

gordoste@rpi5:~/i2smulti $ diff graph-working.dts graph-broken.dts
48,50c48,50
<                       port@0 { reg = <0>; link_dac: endpoint { 
remote-endpoint = <&codec_dac>;  };};
<                       port@1 { reg = <1>; link_adc: endpoint { 
remote-endpoint = <&codec_adc>;  };};
<                       port@2 { reg = <2>; link_cpu: endpoint { 
remote-endpoint = <&cpu_i2s>;    };};
---
>                       port@0 { reg = <0>; link_cpu: endpoint { 
remote-endpoint = <&cpu_i2s>;    };};
>                       port@1 { reg = <1>; link_dac: endpoint { 
remote-endpoint = <&codec_dac>;  };};
>                       port@2 { reg = <2>; link_adc: endpoint { 
remote-endpoint = <&codec_adc>;  };};


Regards
Stephen